Merits and Limitations of Dynamic Vapor Sorption Studies on the Morphology and Physicochemical State of Freeze-Dried Products

Edible Pleurotus eryngii Papery Food Prepared by Papermaking Process

The objective of the current study was to evaluate the feasibility of papery food with Pleurotus eryngii (P. eryngii) as a raw material using the papermaking process. The physical, chemical, structural, and thermal degradation properties were studied as well as the sensory evaluation of the papery food from P. eryngii mycelia (PMP), stems (PSP), caps (PCP), and whole fruiting bodies (PEP). The results indicated that the colors from PSP, PCP, and PEP were clearly different from PMP. Thicker PSP and PMP had a smoother surface and better crispness compared to PCP. Moreover, PSP had better moisture resistance and thermal decomposition performance compared to the other groups. Nutritional composition and Fourier-transform infrared spectroscopy suggested abundant polysaccharide and protein content in all of the papery food. Finally, sensory evaluation showed that the formability, mouth feel, and overall palatability of PSP and PMP were more popular among consumers. Overall, this study provides a novel method for the preparation of papery food and provides a potential new mechanism for the further development and utilization of the fruiting bodies and mycelium of P. eryngii.

Preserving the Integrity of Liposomes Prepared by Ethanol Injection upon Freeze-Drying: Insights from Combined Molecular Dynamics Simulations and Experimental Data

The freeze-drying of complex formulations, such as liposomes, is challenging, particularly if dispersions contain residual organic solvents. This work aimed to investigate the effects of possible protectants, namely sucrose, trehalose and/or poly(vinyl pyrrolidone) (PVP), on the main features of the dried product using a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)-based liposomal dispersion prepared by ethanol injection and containing ethanol up to 6%, as a model. The interactions among vesicles and protectants were preliminary screened by Molecular Dynamics (MD) simulations, which have been proved useful in rationalizing the selection of protectant(s). The freeze-drying protocol was based on calorimetric results. Overall data suggested a stronger cryo-protectant effect of trehalose, compared with sucrose, due to stronger interactions with the DPPC bilayer and the formation of highly ordered clusters around the lipids. The effect further improved in the presence of PVP. Differently from the other tested protectants, the selected trehalose/PVP combination allows to preserve liposome size, even in the presence of 6% ethanol, as demonstrated by Nanoparticle Tracking Analysis (NTA). Nevertheless, it should be also underlined that cakes blew out at an ethanol concentration higher than 1% v/v, probably due to the poor cohesion within the cake and solvent vapour pressure upon sublimation.

Exploring the solid-state phases and thermodynamics of calcium l-lactate

Calcium l-lactate, an organic salt derived from l-lactic acid, is used in many fields such as food, pharmaceutical or cosmetic industry. To this date, its solid-state thermodynamics are still poorly understood: a pentahydrate crystalline and anhydrate amorphous forms were already characterized, and potential other hydrates mentioned in literature. For the development of a robust crystallization process or down-line handling of this compound, it is important to know and understand the relationship between the different solid forms to prevent uncontrolled crystallization or solid-solid transformation during storage. In this paper, we aimed at identifying and characterizing novel solid forms of calcium l-lactate. Combining analytical techniques, we confirmed the existence of the pentahydrate and an amorphous anhydrate. In addition, we played on temperature and relative humidity conditions to discover three new crystalline forms (a crystalline anhydrate, monohydrate and dihydrate). This paper is the first occasion where these forms were successfully isolated and characterized.

Characterizing Hygroscopic Materials via Droplet Evaporation

Hygroscopic materials are widely used as desiccants for applications including food production, packaging, anti-icing, and gas storage. Current techniques for quantifying the hygroscopicity of materials, such as the use of a tandem differential mobility analyzer or a gravimetric vapor sorption analyzer, require complex and expensive setups. Here, we show that the hygroscopicity of any bulk material can be simply characterized by suspending it above a deposited droplet and measuring the droplet's evaporation rate. By controlling the temperature of the droplet to correspond to the dew point, we ensured that any evaporation was directly correlated with diffusive transport into the low-pressure hygroscopic material. Using Fick's law, the effective water vapor concentration of each material was extracted and nondimensionalized by the saturation concentration to obtain a hygroscopic index. This nondimensional index ranges from 0 (no hygroscopicity) to 1 (null vapor pressure) and can also be conceptualized as 1 - a_w, where a_w is the material's water activity.